Continued characterization of normal B cell development pathway and the effects of allotype suppression on B cell development in suppressed mice: identification of T cell requirements for B cell differentiation through the various stages of development; identification of suppressive influences which restrict affinity maturation and B cell development; characterization of the T cells and soluble T cell factors involved in allotype suppression. Continued exploration of mechanisms involved in regulating IgG antibody response affinities: study the role of IgD in affinity maturation of the memory populations; study the role of hapten-specific suppression in controlling the expression of high affinity memory B cells in in situ antibody responses. Characterization of the relationships between carrier-specific help, allotype suppression and the induction of hapten-specific suppression: Delineation of regulatory circuit interactions between allotype suppressor T cells and hapten-specific helper T cells; determination of whether carrier-specific helper T cells participate in the induction of hapten-specific helper T cells and/or hapten-specific suppressor T cells. Exploration of mechanism involved in induction of allotype suppression: Identification of genetic influences; serological characterization of inducing antibodies; identification of cell interactions involved in suppression induction.